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E. HARTMANN. RAILWAY BRAKE OPERATING BY AIR PRESSURE 0R VACUUM. N0. 448,833; Patented May. 24, 1891.

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7 E. HARTMA NN. RAILWAY'BRAKE OPERATING BY AIR PRESSURE OR VACUUM.

Patented Mar. 24,1891:

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PATENT ERNST HARTMANN, OF DUSSELDORF, GERMANY.

SPECIFICATION forming part of Letters Patent No. 448,833, dated March 24, 1891.

7 Application filed July 21, 1890. Serial No- 359,393. (No model.)

To all whom it may concern.-

Be it known that I, ERNST HARTMANN, of Dusseldorf, Prussia, in Germany, have invented a certain new and useful Improvement in Brake-OperatingMechanis1n,of which the following is a specification.

It is intended mainly for railroad-cars and will be described as thus applied.

The objectof the invention is to provide for easily adapting a car to be attached to and worked with other cars in which either a strong pressure of air may be in the pipe or a vacuum may be formed therein. My improved brake mechanism will work with either system, and the adjustment may be effected at will by simply closing one cock and opening another. I designate my cylinder a double-working pneumatic or vacuum cylinder, or, more briefly, a double-workin g cylinder.

The accompanying drawings form a part of this specification, and represent what I esteem the best means of carrying out the in- I vention with several modifications.

Figure 1 is a side elevation, partly in vertical section, of a portion of a car according to the invention. Fig. 2 is a corresponding view of a small portion on a larger scale, showing a modification. Fig. 3 is a side elevation, and Fig. 4. a plan view, showing the invention applied to hand braking mechanism. Fig. 5 is an elevation corresponding to Fig. 3.

Similar letters of reference denote corresponding parts in all the figures where they occur.

A is the substantial frame-work of the car; A, the ordinary jaws, which perform their usual functions of guiding the axle-boxes in their up-and-down motion in traversing over irregularities in the road, and {k a cyl nder in which plays a piston B, having a pistonrod 1) extending out through a stuffing-box.

Referring to Figs. 1 and 2, O and C are cocks connecting the two ends of thecylinder A with the main pipe 0, which traverses the car'from end to end, and is connected 'by hose-pipe with a reservoir 'or considerable chamber, (not shown,) in which by an air-compressor or an air-pump adapted to make and -maintain a vacuum operated either constantly or at intervals or by other means (not shown) a considerable pressure above atmosphere is maintained or a strong vacuum is maintained. The condition may be either.

In operating with a high pressure of air in the pipe 0 air is first introduced to the cylinder through the cock 0', and piston 13 is driven from that end of the cylinder until it arrives at about the mid-length of the cylinder A Where the air commences to flow past the piston through the passage to, arranged to serve as a by-pass. The piston after passing both ends of the passage a comes to rest with a good pressure of air on each face and the brake completely out of action. It will remain in this condition any period. When the brake is to be applied, the air under pressure is allowed to escape from the pipe C,

which immediately reduces the pressure in the end of the cylinder connected thereto by the open cook 0, while the other end of the cylinder A retains its air at full pressure, the cock (3 being all the time closed. Thus conditioned the piston will be driven rapidly toward the cock 0. During the time it is moving through the mid-length part of the cylinder some air will escape by flowing past the piston through the passage a; but this amount will be small, and so soon as the piston has passed both ends of the passage d the pressure remaining will be effective to urge the piston without further loss. The result is the prompt and edective pressing of the wheel D against the drum E on the bearing-axle c and. the rapid applying of the brakes, which may be What is known as the Schmidt system, as set forth in the United States patent to J. H. Schmidt, dated January 4, 1881, No. 236,184,.

When the brake is to be released, the operator admits air at high pressure from any suitable storage-reservoir again into the pipe 0, which instantly acts through the open cock 0 to repeat the operation first described, driving the piston again through the cylinder- A past the pipe a, which again gives a'supply of air to be stored beyond the piston ready to again act when the piston is again relieved from pressure on the opposite side, and so on. lVhenever the wheel D is thus removed out of contact with the drum E, the parts are at liberty to rapidly resume their original positions.

In operating through vacuum or partial vacuum in the pipe 0 and its connections the cock G is closed and the cock C is opened. A vacuum is thus formed in the end C of the cylinder or the end connected to C and the piston moves as before toward the cock C In passing the by-pass a some of the air in the end nearest 0' passes, and ultimately the piston and its connections come to rest with a tolerable vacuum on each face of the piston. IVhen thus worked, the brake is to be applied by the attendant by operating avalve, (not shown,) which maybe at any convenient distance, and admits air at atmospheric press ure to the pipe 0, and this through the open cock 0 fills one end of the cylinder A, that end farthest from the brake, the end to the left in Figs. 1 and 2, which immediately drives the piston forcibly toward the other end of the cylinder, the right-hand end in Figs. 1 and 2. In the movement, as before, some air will flow idly past the piston through the passage a; but the motion being rapid and the passage small there will still remain a tolerable vacuum in the other end of the cylinder, and the wheel D will be pressed and held against the rapidly-revolving drnin E with the effect to apply the brake instantly and strongly, as before.

If in the exigencies of railway practice my car passes over to a railway having the vacuum-brake system, the attendant has simply to see that the cock 0' is closed and the cock C is open. If, on the contrary, my car (by which I mean a car of any ordinary or suitable construction in other respects, and having my brake apparatus) passes over to a railway having the air-brakes sometimes called pneumatic, the attendant closes the cock C and opens the cock C, with the effect before minutely described. The movement of the piston too far is prevented and the motion too far toward the cock C by the abutting of a wide part of the loop I) against the stuffingbox of the cylinder A and the motion in the opposite direction by the contact or the cushioning of the piston against the end of the cylinder adjacent to the cock 0. Any desired high pressure or any desired complete vacunm which. can be established in the pipe 0 may be safely and freely used.

My invention can be used with other than the Schmidt system. Fig. 2 shows a gearwheel engaged with a rack on the extension of the piston-rod, and such gear-wheel may by proper connections actuate the brakeblocks. The cylinder A may also be connected with each compartment of each car in a train or with such compartments as may be desired, so that any passenger in those compartments can effect the required changes in the conditions in the cylinders and in the connecting-pipe C throughout the train and instantly apply the brakes in case of accident.

The mechanism shown in Figs. 3 and 4 is adapted to be worked by hand. Sufticient looseness is provided to allow the brakes to be applied by hand without working the piston and its connections and to allow the reverse conditions, the brakes being applied by the piston without operating the hand mechanism. I have shown this looseness at the joint 1' in Fig. 3.

The force with which the brakes will be applied with a given pressure of air in the pipe 0 or a given vacuum therein may be varied by the obvious expedient of changing the levers or the effective lengths of the levers. Fig. 5 shows such a modification, there beinga series of three holes into which the pin may be shifted.

Myinvention allows the cars to be coupled with others similarly provided or with cars having any other arrangement of pneumatic or vacuum brake. In any and all its forms the mechanism is self-acting. If one or more cars be detached by any accident, both portions of the train will be automaticallystopped.

I claim as my invention- 1. In a mechanism for actuating brakes, the double-working pneumatic or vacuum cylinder A with its inclosed piston B, and connections from the latter to control the brake mechanism, in combination with the car A, conduit or main pipe C and hose or pipes connecting therefrom to each end of the cylinder, and the two cocks C and '0 adapted to allow of operating equally by vacuum or by pressure by opening one or the other cock, as herein specified.

2. In mechanism for actuating brakes, the by-pass passage a in the cylinder A having both its ends opening into the cylinder near the mid-length, in combination with the main pipe C and branch pipes leading therefrom to each end of the cylinder controlled by cocks G 0 and with the piston B and connecting mechanism for controlling the brake action by the motion of the latter, all substantially as herein specified.

3. In mechanism for operating car-brakes, the combinatiomwith the axle c and drum E, fixed thereupon, of the Wheel D, adapted to be thrown in and out of engagement with said drum, conduit C, cylinder A, having by-passage a, cocks G (3 controlling branch pipes leading from said conduit to the two ends of said cylinder, double'operating piston B, and connections therefrom to the wheel, all arranged to operate substantially in the manner and for the purpose set forth.

In testimony whereof I have hereunto set my hand, at Berlin,-Germany, this 19th day of June, 1890, in the presence of two subscribing witnesses.

ERNST IIARTM ANN.

\Vitnesses:

CARL GRONERT, GEO. II. MURPHY. 

